1. Field of the Invention
The present invention relates to a control device for a synchromesh automatic transmission for a vehicle, which can stably maintain a time for changing gears.
2. Discussion of Background
An example of a control device for a synchromesh automatic transmission for a vehicle is disclosed in, for example, Japanese Unexamined Patent Publication JP-A-63-270252, wherein an opening degree of a throttle is controlled to maintain a change between a rotational speed of a combustion engine at time of releasing an electromagnetic clutch for changing transmission gears and a rotational speed of the combustion engine at time of recoupling the electromagnetic clutch within a predetermined range, and a control input is corrected by a learning routine at every gear changing operation in order to deal with scattering and various conditions of the combustion engine in a structure of coupling the combustion engine with a synchromesh automatic transmission by the electromagnetic clutch, whereby a shock caused by a gear changing operation is relaxed.
A shifting device changing the gears of the transmission in this conventional technique is constructed such that a pair of three-position oil pressure cylinders operating a shifting and selecting lever in an actual direction and a rotational direction, a shifting rod is selected by driving the three-position oil pressure cylinder for selecting the gears, and the selected shifting rod is moved by driving the three-position oil pressure cylinder for shifting the gears to change gear positions. Other than the hydraulic shifting device, an electromotive synchromesh automatic transmission, by which gears are shifted and selected in use of two motors, is generally used. A gear change operation in this electromotive synchromesh automatic transmission controls a driving quantity of a shifting and selecting actuator using a deviation between a shifting and selecting position detected by a shifting and selecting position sensor and a target shifting and selecting position as a parameter, wherein a feedback control of the positions is performed in use of a PID control, in which proportional elements, integral elements, and differential elements are distinguished.
In the conventional synchromesh automatic transmission changing the gear positions by controlling the shifting and selecting positions, the positions are controlled by setting a value of parameters for the positional feedback control. However, because the parameters are fixed values in the conventional device, there are problems that convergence of an actual shifting position into a target shifting position is deteriorated, a time required for a shifting operation is prolonged to give an uncomfortable feeling to a driver at time of changing the gears, and a drive feeling is deteriorated when a control input, necessary for a shifting operation, is changed by scattering of accuracies of components, changes of conditions in use, aged deterioration, and so on.
It is an object of the present invention to solve the above-mentioned problems inherent in the conventional technique and to provide a control device for a synchromesh automatic transmission which renews controlling parameters by each operation based on an learning value of deviation, obtained from a deviation between a target shifting position and an actual shifting position and a shifting time, and shifting is succeedingly controlled by thus renewed parameters to enable a shifting operation constantly within a short time even though driving quantity necessary for the shifting operation is varied.
According to a first aspect of the present invention, there is provided a control device for a synchromesh automatic transmission comprising: an input shaft coupled to a crank shaft of a combustion engine through a clutch mechanism; an output shaft coupled to the input shaft by gears; a plurality of groups of transmission gears having different gear ratios and interposed between the input shaft and the output shaft; a coupling mechanism selectively coupling one of the plurality of groups of the transmission gears and the output shaft; a shifting and selecting actuator controlling a shifting position and a selecting position of the coupling mechanism; a shifting and selecting position sensor detecting a position controlled by the shifting and selecting actuator; and a control unit controlling a control input for the shifting and selecting actuator by a feedback of a position detected by the shifting and selecting position sensor, wherein the control unit detects a deviation between an actual control input by the shifting and selecting actuator and a target control input, and a next target control input is corrected using a quantity of the deviation as a learning value.
According to a second aspect of the present invention, there is provided the control device for the synchromesh automatic transmission, wherein the control unit detects the deviation between the actual control input of the shifting and selecting actuator and the target control input, and a lapse of time for changing the gears, and a next target control input is corrected based on the deviation and the lapse of time.
According to a third aspect of the present invention, there is provided the control device for the synchromesh automatic transmission, wherein the shifting and selecting actuator is controlled by a positional control by a PID control, and the target control input is corrected by proportional elements in the PID control.